The objective of our program project in aging at Beth Israel Hospital is to establish a productive and integrated program of clinical research in the neurological concomitants of aging and dementia. The project is multi-disciplinary in nature and involves close collaboration between researchers in four different medical centers. The two studies that comprise the program project are primarily correlational investigations. That is, their goal is to determine the relationship between neuropsychological, neurophysiological (i.e., EEG's and EP's) and neuroanatomical (i.e., CT scans) measures in healthy aging individuals and in patients with Alzheimer's disease. In addition, Alzheimer's patients are being treated with lecithin in order to determine whether the progress of disease can be reversed or retarded by cholinergic therapy. Preliminary evaluations of CT scan information indicate that while measurements of ventricular and sulcal size do not contribute to diagnostic accuracy, the mean CT density numbers of white and gray matter at specific locations in the brain are significantly different in demented vs. non-demented patients. Since there is practically no overlap in the mean CT density numbers of these tissue areas, it is hoped that the CT scan investigations may facilitate the diagnosis of Alzheimer's disease.